The presence of antimicrobials in root, hypocotyl and cotyledon homogenates of Norway spruce was studied using in vitro assays with soil-borne pathogens. For the studies presented here Norway spruce (Picea abies (L.) Karst.) as a typical host and forest tree and Pythium as a typical soil-bome pathogen were used. The highly virulent species Pythium ultimum and the less virulent species Pythium irregulare were chosen for all experiments. They are both the causal agents of damping-off disease, which can affect plants at a very early stage. The strongest antimicrobial effect was observed using medium prepared from older seedlings and containing extracts from cotyledons. The influence of various treatments on antimicrobials accumulation in spruce extracts was also tested. Seed coat shedding was observed to affect mortality of Picea abies seedlings infected by Pythium. Seedlings which had shed their seed coats were more resistant to Pythium attack. This phenomenon could be correlated with antimicrobial production in well developed cotyledons.